package com.zjw.algorithm.ready1;

import com.zjw.algorithm.utils.TreeNode;

public class _最近公共祖先 {

    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        if (root == null) {
            return root;
        }

        if (root == p || root == q) {
            return root;
        }

        TreeNode left = lowestCommonAncestor(root.left, p, q);
        TreeNode right = lowestCommonAncestor(root.right, p, q);

        if (left != null && right != null) {
            return root;
        }

        if (left != null) {
            return left;
        }

        if (right != null) {
            return right;
        }

        return null;
    }
}
